Reference-free method for conducting EWAS while deconvoluting DNA methylation
arising as mixtures of cell types. The older method
(Houseman et al., 2014,<doi:10.1093/bioinformatics/btu029>) is similar to
surrogate variable analysis (SVA and ISVA), except that it makes additional use
of a biological mixture assumption.
The newer method (Houseman et al., 2016, <doi:10.1186/s12859-016-1140-4>) is similar
to non-negative matrix factorization, with additional constraints
and additional utilities.